LSD noises - what's normal?

[BenzBoy]

I think I have an LSD in the rear of my Nissan Patrol (I need to check to make sure, but info is difficult to come by.)

After a long drive of, say, more than 40 miles I get a groaning noise from the back end on tight, low-speed turns. This only seems to happen after long runs. There's no other symptoms - the vehicle turns well enough and the tyres don't seem to be scrubbing etc.
The 4x4 is definitely disengaged, and there is no diff lock unless I haven't found it yet!

I'm looking at changing the oil anyway, but I'm not sure whether the noises are normal or not?

[Bozwell]

if it's a plated diff then it'll need an addative to stop the plates juddering. BPA which is a company that build diffs all the time advised using an addative even with LSD specific oil.

[ChasR]

Regarding LSD specific oils, is it not wise to go with an old with a GL4 rating and to stay away from anything with a GL5 rating on it due to certain additives playing havoc with LSDs on oils with a GL5 rating.

[BenzBoy]

Thanks for the replies. The handbook recommends GL5. And it's 80W90 whether it has an LSD or not, apparently! Although it does say it needs an "LSD Specific" oil. Presumably it has a friction modifier or something.

It's getting an oil change tomorrow, so I'll see if it makes any difference after that.

[Blown_Imp]

The Celica has a big tight plate diff, it scared the bejeebus out of me on the first drive! It clonked and juddered like nothing else at low speed, must quieter once moving. I have since rebuilt it and put in some Motul LSD oil, big difference in the harshness but still noisy

[BenzBoy]

Just thought I'd update - The oil was changed, and after a long run at the weekend the diff was quiet while negotiating the car park with no clutch chatter. I don't know whether the oil was just old, or the wrong grade, but anyhow the new stuff has done the trick. Also, I do definitely have an LSD in there.

Thanks for all the help and replies